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Proactiveness, Business Ties, and Technological Innovations in Emerging Economies : A Tale of Two Paths
No full textZTF SN Ia DR2 follow-up : Characterization of subluminous Type Ia supernovae in the ZTF DR2 full sample
No full textThe Zwicky Transient Facility Data Release 2 (ZTF DR2) includes a total of 3628 Type Ia supernovae (SNe Ia), providing the largest and most complete sample of spectroscopically confirmed SNe Ia at low redshift to date. In this paper, we present a photometric and spectroscopic analysis of 124 subluminous SNe Ia, the largest sample of spectroscopically classified subluminous Type Ia supernova observed with a single instrument, comprising 87 91bg-like, 12 86G-like, 18 04gs-like, and 7 02es-like events. We complement the published DR2 SALT2 light-curve parameters with new parameters obtained using template-based fits from SN OO P Y . We measured the expansion velocities and pseudo-equivalent widths ( pEW ) of key spectral features using SPEXTRACTOR . Next, the spectral averages were constructed for each subluminous subtype, binned by phase. We also analyzed the host galaxy environments, both global and local, in terms of g − z color, stellar mass, and directional light radius ( d DLR ). We found that all subluminous SNe Ia (except the 02es-like subtype) are intrinsically red. This is made evident when we separate the extrinsic color components from intrinsic ones. Since SALT2 has not been trained on subluminous SNe Ia, it compensates for their redder colors by inflating the c parameter, thereby extending the luminosity-width relation to negative values of x 1. As expected, all subluminous SNe Ia fall within the cool region of the Branch et al. (2006, PASP, 118, 560) diagram, with the exception of 02es-like events, which display lower Si II λ 5972 pEW values. All subluminous subtypes tend to occur in more massive, redder host galaxies and in the reddest local environments within their stellar mass bins. Notably, 91bg- and 86G-like SNe Ia explode at significantly larger normalized galactocentric distances. Finally, we identified the pEW of the blended Ti II +Si II +Mg II absorption feature at 4300 Å, along with s BV , as robust and sufficient indicators for subclassifying subluminous SNe Ia
Ultra-faint Milky Way Satellites Discovered in Carina, Phoenix, and Telescopium with DELVE Data Release 3
No full textWe report the discovery of three Milky Way satellite candidates: Carina IV, Phoenix III, and DELVE 7, in the third data release of the DECam Local Volume Exploration survey (DELVE). The candidate systems were identified by cross-matching results from two independent search algorithms. All three are extremely faint systems composed of old, metal-poor stellar populations (τ ≳ 10 Gyr, [Fe/H] ≲−1.4). Carina IV (MV = −2.8; r1/2 = 40 pc) and Phoenix III (MV = −1.2; r1/2 = 19 pc) have half-light radii that are consistent with the known population of dwarf galaxies, while DELVE 7 (MV = 1.2; r1/2 = 2 pc) is very compact and seems more likely to be a star cluster, though its nature remains ambiguous without spectroscopic follow-up. The Gaia proper motions of stars in Carina IV ( M⋆=2250−830+1180M⊙ ) indicate that it is unlikely to be associated with the LMC, while DECam CaHK photometry confirms that its member stars are metal poor. Phoenix III ( M⋆=520−290+660M⊙ ) is the faintest known satellite in the extreme outer stellar halo (DGC > 100 kpc), while DELVE 7 ( M⋆=60−40+120M⊙ ) is the faintest known satellite with DGC > 20 kpc
Neural Differentiation in Deep Networks : A Theoretical Framework for Expressivity and Representational Diversity
Get PDFWe begin by developing a mathematical framework of neural differentiation, formulated at the level of individual neurons. This framework formalizes the principle that each neuron should acquire a distinct representational role within the network, thereby avoiding redundancy and maximizing collective expressivity. Differentiation is quantified through the Neural Differentiation Index (NDI), a loss-aware measure that characterizes neuron significance from geometric, informational, and curvature-based perspectives within a unified framework. The NDI enables a rigorous characterization of how strongly a neuron diverges from its peers in both function and importance, and supports theoretical guarantees: we establish formal bounds on the error increase under NDI-guided elimination, thereby providing provable safety margins for network compression. Building on this foundation, we introduce Neural Differentiation Pruning (NDP) as a practical instantiation. NDP leverages NDI to perform adaptive, training-time neuron sparsification, followed by targeted fine-tuning, guiding networks toward compact yet highly differentiated backbones. Although the terminology draws loose intuition from biological differentiation, the framework is fully mathematical and architecture-agnostic. Experiments on modern vision benchmarks and architectures show that NDP achieves substantial structured sparsity while maintaining—or even improving—accuracy and robustness, underscoring the practical impact of the differentiation framework
A Study of the Avalanche Multiplication and Excess Noise in Al x In 1– x As γ Sb 1- γ Avalanche Photodiodes Lattice-Matched to GaSb
No full textHigh-sensitivity linear-mode avalanche photodiodes (APDs) that operate beyond 1.65 μm and up to 2 μm require a narrow bandgap that also gives rise to high dark currents, especially when subject to the large electric fields necessary for avalanche multiplication. This has led to increasing interest in separate absorption, charge, and multiplication (SACM) detectors where the narrow bandgap absorber has a low electric field and the wider bandgap multiplication region provides the gain. A systematic study of Al0.7In0.3As0.31Sb0.69 grown lattice-matched on GaSb as the multiplication layer has been undertaken on p–i–n structures varying in width from 0.1 to 1.5 μm and the ionization coefficients and excess noise extracted over a wide electric field range (195 kV/cm–830 kV/cm). When integrated with a lattice-matched Al0.3In0.7As0.64Sb0.36 absorption layer, such an SACM APD is found to demonstrate a quantum efficiency of 64% and 10% for the wavelengths of 1.55 and 2 μm, respectively, at punch-through, without any antireflection coating. The device shows a maximum avalanche gain of 197 with an excess noise of 3.1 at a gain of 10. Such APDs can be potentially used in a receiver for many photon-starved applications, including gas sensing and LiDAR
Movement patterns and connectivity of gilthead seabream ( Sparus aurata ) in the NW Mediterranean Sea
Get PDFBackground: Animal movement underpins critical ecological processes and shapes ecosystem resilience. In marine systems, understanding the spatial ecology and connectivity of exploited species is essential for informing conservation and sustainable fisheries management. Despite their ecological and economic importance, the spatio-temporal movement of gilthead seabream (Sparus aurata) in the Mediterranean Sea remains poorly understood. Methods: We leveraged the largest acoustic telemetry dataset ever collected in the Mediterranean as part of the project CONNECT-MED and RESMED, tracking 222 tagged seabream over three years (2019–2022). Using an array of more than 180 strategically positioned acoustic receivers across the Gulf of Lion in both lagoons and the sea, we analysed over 700,000 detections spanning a longitudinal gradient of 200 km. Using individual-based spatial network analysis, we quantified movement dynamics, space use, and connectivity. Results: Seabream showed strong seasonal migrations, with wide (> 180 km for some individuals) spatial dispersal during spawning (October–March) and localized movements whilst foraging (April–September). Eastward and southward migration linked lagoon nurseries/foraging areas to offshore spawning areas. The Marseille area (Calanques National Park and Côte Bleue Marine Park) was identified as a major spawning region used by fish across the Gulf of Lion. Movement varied with fish size, with larger fish having more complex and dynamic networks. Autumn saw synchronous lagoon emigration and aggregation at spawning sites, with multi-year site fidelity. Conclusions: Our findings demonstrate size-dependent movement strategies in gilthead seabream and reveal structured connectivity linking lagoon foraging areas to offshore spawning grounds. The concentration of spawning activity near Marseille identifies a key regional hotspot of ecological and management importance. Incorporating these connectivity patterns, ontogenetic shifts, and spatial behaviours into fisheries management will be essential for sustaining seabream populations across the northwestern Mediterranean
Electrode-dependent spin and thermoelectric transport in M@C80 (M=Fe, Co, Ni) molecular junctions
Get PDFThe ability to engineer molecular junctions with tunable spin and thermoelectric properties is central to the development of high-performance nanoscale devices. In this work, we investigate endohedral fullerenes M@C80 (M=Fe, Co, Ni) contacted by gold and graphene electrodes using density functional theory combined with the non-equilibrium Green’s function formalism. Encapsulation of transition-metal atoms inside the C80 cage induces pronounced charge transfer, orbital hybridization, and spin splitting, leading to strongly modulated and energy-selective transmission spectra. The Au–Fe@C80–Au junction exhibits the highest spin polarization and near-unity transmission at the Fermi level, making it particularly suitable for spintronic applications. In contrast, the Gr–Co@C80–Gr junction displays an exceptionally large thermoelectric response. The thermoelectric figure of merit is reaching ZT > 1000 which originates from sharp, asymmetric transmission resonances near the Fermi energy and enhanced π–π coupling with graphene. These values represent upper theoretical limits within a coherent electronic transport regime and do not imply a violation of thermodynamic constraints, as the thermoelectric efficiency remains bounded by the Carnot limit. The Ni@C80 junction shows broader transmission features, which are favorable for energy-selective transport. A comparative analysis of electrode materials reveals that gold provides stronger and more stable molecule–electrode coupling with higher electrical conductance, whereas graphene enables superior energy filtering and an enhanced Seebeck response
Global evidence that plant diversity suppresses pests and promotes plant performance and crop production
Get PDFThe diversity-productivity relationship suggests that increasing plant species could increase primary productivity, with this effect being explained in part by the suppression of plant antagonists. We conducted a global synthesis of 609 studies to investigate how plant diversity affects plants and their antagonists. Here we show that increasing plant species consistently promotes plant performance and suppresses antagonist performance in agro-ecosystems, grasslands and forests, for herbaceous and woody plants, across tropical and temperate zones, and for replacement series and additive experimental design studies. Crop diversification (for example, intercropping and cover cropping) indirectly promotes crop production through the suppression of pests. This shows that diversifying planting systems can increase productivity while reducing reliance on synthetic pesticides, offering a sustainable pathway for agriculture from subsistence to large-scale agriculture. Overall, these results suggest that crop diversification has considerable potential to support sustainable agro-ecosystems that benefit productivity while reducing reliance on synthetic pesticides